Conventional precharge is broadly classified into three schemes, that is, 1) shorting of signal lines in odd numbered columns and even numbered columns, adjacent to each other, respectively, 2) shorting of all signal lines, and 3) shorting of all signal lines to a common electrode, and driving capacity and power consumption, required for writing (charge/discharge) of signal voltages to liquid crystal capacitance, is reduced by temporarily executing any of these schemes.
The following Patent Document, namely, JP-A 1999-30975 is cited as an example thereof.
The present technological trend is that the 2-DOT reverse signal line driving method (a driving method whereby signals are reversed for every two horizontal scanning periods) is in the mainstream in order to achieve lower power consumption of a liquid crystal display device. In this case, the precharge executed simply for every two horizontal scanning periods results in deterioration in display quality, so that it is a general practice to execute the precharge for every one horizontal scanning period. The following Patent Document, namely, JP-A 1999-095729 is cited as an example thereof.
Shorting for attaining the conventional precharge as disclosed in JP-A 1999-095729 is important to solve a problem of time required for charge/discharge of source lines. With the shorting by the conventional precharge, however, potentials of the source lines can reach only up to around the potential of the common electrode. Accordingly, in order to implement charge/discharge of the signal lines after the precharge, driving is required for half of charge/discharge that would be required in case the shorting by the precharge is not employed, so that reduction in power consumption is not sufficient in this case.